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NON-UNIQUE SOLUTIONS FROM SURFACE ELASTICITY FOR FUNCTIONALLY GRADED MATERIALS

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Acta Mechanica Solida Sinica 2014年第4期27卷 364-372页

作者： jun zhu Weiqiu Chen Jiqing Jiang jun Zeng College of Mechanical Engineering Zhejiang University of Technology State Key Lab of CAD & CG Zhejiang University Department of Engineering Mechanics Zhejiang University Zhejiang University City College

This paper considers the unusual behavior of functionally graded materials/structures when the surface effect is involved. It is found that on the assumption that the surface energy is not positive semi-definite, the solution can be non-unique. Several examples are given for simple spherically-symmetric and axisymmetric FGM bodies with surface effects characterized by Gurtin-Murdoch surface elasticity. The results show that the conditions for non-uniqueness of solution emerge when the magnitude of negative effective surface modulus is of the order of a characteristic dimension of the problem multiplied by the bulk modulus near the surface, which is quite different from that for homogeneous materials.

关键词： functionally graded material surface theory non-uniqueness elasticity

Michael addition-based cyclization strategy in the total synthesis of Lycopodium alkaloids

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Science China Chemistry 2016年第9期59卷 1079-1087页

作者： Lin-Rui Zhong zhu-jun Yao State Key Laboratory of Coordination Chemistry Institute of Chemical Biology and Drug Innovation School of Chemistry and Chemical Engineering Collaborative Innovation Center of Chemistry for Life Sciences Nanjing University

Lycopodium alkaloids, a unique family of biologically important natural products isolated and characterized from various species of Lycopodium(sensu lato), have attracted extensive attention from chemists and pharmacists in the past three decades. Michael addition-based cyclization has been successfully employed as an elegant and efficient ring-construction protocol of constructing key cyclohexanone intermediates in the total synthesis of Lycopodium alkaloids. This mini-review chooses and summarizes several representative total syntheses of various Lycopodium alkaloids in which intramolecular Michael addition severed as the key methodology.

关键词： Lycopodium alkaloid Michael addition cyclization total synthesis

Flow-Induced Vibration of Four Cantilever Cylinders Arranged in A Square Configuration

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China Ocean Engineering 2021年第6期35卷 891-904页

作者： zhu Hong-jun LIU Wen-li WANG jun-lei State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Southwest Petroleum UniversityChengdu 610500China School of Mechanical and Power Engineering Zhengzhou UniversityZhengzhou 450000China

Flow-induced vibration(FIV)of four separately mounted cantilever cylinders are experimentally investigated in a water *** four cylinders with top ends screwed vertically into a turntable platform are subjected to uniform flows with Reynolds number ranging from 3840 to 16520.A non-intrusive measurement with high-speed cameras is employed to simultaneously capture the time-varying in-line and cross-flow vibrations in the reduced velocity range of *** results highlight the continuous adjustment of flow regime caused by the spatial-temporal alteration of ***,the space-time varying flow interference contributes to the occurrence of multiple response *** transition from a dominant frequency to a broad-band response illustrates the enhancement of wake *** combination of wake flow interactions results in the irregular oscillation trajectories and the appearance of a response trough with the associated switching in vortex shedding *** dual-resonance phenomenon is observed in the four cylinders due to the complicated wake-structure *** greatest mechanical energy possessed by the four cylinders in an in-line square arrangement is mainly resulted from the downstream cylinders,signifying the positive role of wake excitation in extracting hydrokinetic energy from ambient flow.

关键词： flow-induced vibration mechanical energy cantilever cylinder time-varying spacing attack angle

Could π-aromaticity cross an unsaturated system to a fully saturated one?

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Chinese Chemical Letters 2024年第6期35卷 298-302页

作者： Shicheng Dong jun zhu State Key Laboratory of Physical Chemistry of Solid Surfaces Collaborative Innovation Center of Chemistry for Energy Materials(iChem)Fujian Provincial Key Laboratory of Theoretical and Computational ChemistryCollege of Chemistry and Chemical EngineeringXiamen UniversityXiamen 361005China School of Science and Engineering The Chinese University of Hong KongShenzhen 518172China

The classification of π-/σ-aromaticity depends on the electrons with the dominating ***,π-andσ-aromaticity are used to describe the unsaturated and saturated systems,***,it is rarely reported that π-aromaticity is dominated in a saturated *** we demonstrate that π-aromaticity could be dominating in several fully saturated four-membered rings(4MRs),supported by various aromaticity indices including ΔBL,NICS,EDDB,MCI,and Ad *** origin of suchπ-aromaticity in saturated rings could be attributed to an introduction of two additional electrons into the π-type LUMO of the parent neutral *** findings represent a novel approach to achieve π-aromaticity into a fully saturated system which has traditionally been dominated by σ-aromaticity.

关键词： π-Aromaticity Saturated rings Silicon

Antiaromaticity-promoted radical anion stability in α-vinyl heterocyclics

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Organic Chemistry Frontiers 2022年第5期9卷 1427-1436页

作者： Lu Lin jun zhu State Key Laboratory of Physical Chemistry of Solid Surfaces Fujian Provincial Key Laboratory of Theoretical and Computational ChemistryDepartment of ChemistryCollege of Chemistry and Chemical EngineeringXiamen UniversityXiamen 361005People’s Republic of China

As an electron-rich species,radical anions have a wide range of applications in organic *** addition,aromaticity is an essential concept in chemistry that has attracted considerable attention from experimentalists and... 详细信息

关键词： synthesis radical heterocyclic

Influences of traditional Chinese medicine intervention on the bone growth and metabolism of rats with simulated weightlessness

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Asian Pacific Journal of Tropical Medicine 2013年第3期6卷 224-227页

作者： jun zhu Department of Orthopaedics People's Hospital of Zhengzhou

Objective:To prohe into the influences of Chinese herbal compound on the growth and metabolism of weight-bearing bones of tail-suspended ***:Twenty-four male St) rats were randomly divided into blank conlrol group ***-suspended conlrol group(eight) and Chinese medicine treatment group leighti according to their *** treatment was done for the blank conlrol *** distilled water lavage was performed daily for the tail-suspended control *** the basis of the tail-suspended rat model,the rats were given Chinese herbal compound lavage every day in Chinese medicine treatment *** compound includes mulberry,Poria cocas and barbary *** lest cycle was four *** rats were killed after the *** right femoral bone was taken out for the physical measurements, and the left femoral bone was for the three-point beading *** influences of Chinese herbal compound on femoral hone growth and biomechanicsl properties of simulated weightlessness rats were ***:(1) After simulated weightlessness(tail-suspension),compared with the blank control group,all the physiological indexes of rat femoral bone decreased in tailsuspended group and Chinese medicine treatment group(P<0.05).The strength and rigidity of rat femoral bone decreased in tail-suspended group(P<0.01).the maximum load and rigidity coefficient also decreased with the inereasing toughness coefficient in the control group(P<0.01). i2i After the countermeasure of Chinese herbal compound,each biomcchanical indexes showed the tendency of increasing in Chinese medicine treatment group,and theses indexes were close to those of the blank control group(P<0.05),which indicated that(he bone loss caused by simulated weightlessness was ***:Chinese herbal compound for tonifying kidney could effectively prevent the bone loss and have some enhancements on the bone hiomechanical properties.

关键词： Chinese herbal compound Simulated weightlessness Rat femoral bone Biomechanical properties

A Note on the Entropy for Heisenberg Group Actions on the Torus

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Acta Mathematica Sinica,English Series 2024年第10期40卷 2324-2336页

作者： Yu ZHANG Yu jun zhu School of Mathematical Sciences Xiamen UniversityXiamen 361005P.R.China

In this paper,the entropy of discrete Heisenberg group actions is *** α be a discrete Heisenberg group action on a compact metric space *** types of entropies,h and h(α)are introduced,in which h is defined in Ruelle’s way and h(α) is defined via the natural extension of α.It is shown that when X is the torus and α is induced by integer matrices then h is zero and h(α) can be expressed via the eigenvalues of the matrices.

关键词： Entropy Heisenberg group action natural extension torus

Topological Stability and Entropy for Certain Set-valued Maps

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Acta Mathematica Sinica,English Series 2024年第4期40卷 962-984页

作者： Yu ZHANG Yu jun zhu School of Mathematical Sciences Xiamen UniversityXiamen 361005P.R.China

In this paper,the dynamics(including shadowing property,expansiveness,topological stability and entropy)of several types of upper semi-continuous set-valued maps are mainly considered from differentiable dynamical systems points of *** is shown that(1)if f is a hyperbolic endomorphism then for eachε>0 there exists a C^(1)-neighborhood U of f such that the induced set-valued map F_(f,U)has theε-shadowing property,and moreover,if f is an expanding endomorphism then there exists a C^(1)-neighborhood U of f such that the induced set-valued map F_(f,U)has the Lipschitz shadowing property;(2)when a set-valued map F is generated by finite expanding endomorphisms,it has the shadowing property,and moreover,if the collection of the generators has no coincidence point then F is expansive and hence is topologically stable;(3)if f is an expanding endomorphism then for eachε>0 there exists a C^(1)-neighborhood U of f such that h(F_(f,U,ε))=h(f);(4)when F is generated by finite expanding endomorphisms with no coincidence point,the entropy formula of F is ***,the dynamics of the set-valued maps based on discontinuous maps on the interval are also considered.

关键词： Set-valued map orbit space hyperbolic endomorphism perturbation shadowing expansiveness topological stability entropy

Novel high-quality Fano resonance based on metal-insulator-metal waveguide with L-shaped resonators

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Chinese Physics B 2021年第10期30卷 356-363页

作者： Changsong Wu jun zhu College of Electronic Engineering Guangxi Normal UniversityGuilin 541004China

Developing a convenient method that can be routinely applied for ascertaining proportions of different vegetable oils employed in commercial blended edible oils remains a significant *** address this issue by proposing a novel method for detecting volume fraction of different oils based on the fact that these oils are optically transparent and have slightly different indices of refraction at a given temperature and ***,we develop a highly sensitive sensor for measuring the index of refraction of oil blends based on Fano resonance spectra obtained using a metal-insulatormetal(MIM)waveguide structure comprising a gapped straight waveguide coupled with two L-shaped *** index of refraction sensitivity and figure of merit of the structure are calculated based on modeling using the finite element method,and the waveguide structure is accordingly optimized by adjusting the different geometric parameters to achieve a high-quality Fano resonance *** optimized structure achieves an ultra-high refractive index sensitivity of 770 nm/RIU in terms of a refractive index unit(RIU)of ***,a highly stable linear relationship is obtained between the refractive index of mixed edible oils and the resonance *** results demonstrate that the proposed structure can detect slight changes in the volume fractions of the components in blended oils.

关键词： Fano resonance refractive index sensing metal-insulator-metal(MIM)waveguide volume fraction detection